Expandable drill bit and reamer construction



EXPANDABLE DRILL BIT AND RE AMER CONSTRUCTION Filed Aug. 18. 1967 Aug.4, 1970 A. E. BARDWELL 2 Sheets-Sheet l RTTQPNEKS 1970 A. E. BARDWELL3,522,852

EXPANDABLE DRILL BIT AND REAMER CONSTRUCTION Filed Aug. 18. 1967 2Sheets-Sheet 2 .7. 3o 30 g 32 1W 54 30 42 fig/0 46 INVENTOR'.

fiLLE/v E. BFIRDWELL) BV/WMA E7MA, ,(ZZa/wI-Mw QTTORNEVS United StatesPatent 3,522,852 EXPANDABLE DRILL BIT AND REAMER CONSTRUCTION AllenEugene Bardwell, Princeton, N.J., assignor, by

mesne assigmnents, t0 Trident Industries, Inc., Princeton, N.J., acorporation of Delaware Filed Aug. 18, 1967, Ser. No. 661,560

Int. Cl. E21c 13/00 US. Cl. 175--384 9 Claims ABSTRACT OF THE DISCLOSUREDrilling bit and reamer units comprising a shaft or body having areduced lower end. In one preferred embodiment, a row of elongatedchisel bit elements or fingers of carbide or other suitable material ismounted in and extends downwardly from said lower end, the center fingerbeing of bullet-nose shape and the others of one-half bullet-nose form,the flat surface facing in the spin direction. In a second preferredembodiment, two spaced block-like teeth extend down from cavities in thelower end, each tooth being of solid steel or having a cutter insert ofcarbide or other suitable material, said teeth being drawn by a heavybolt towards a partition separating the cavities, and shims forinsertion between each tooth and the partition to compensate for wash orwear of the exposed outer surface of the teeth. Affixed to the shaftabove the cutting elements or to the teeth are spaced reamers formed foreffective reaming and minimum withdrawal sticking.

BACKGROUND OF THE INVENTION Field of the invention The present inventionrelates generally to percussion drilling, and more particularly to novelchurn cable percussion drilling bit and reamer units adapted foradvantageous use with conventional and multiple blow drillingstructures.

Description of the prior art There has long existed the need for churndrill bit and reamer units which are streamlined and reduce to a minimumthe recrushing of rock material previously cut, maintain a straight holeeven against boulders, expandable with the use of simple tools tomaintain size, substantially eliminate resharpening particularly in thefield, do not stick when properly employed, materially in crease theinches per hour drilled thereby over standard equipment, are longlasting, and in which the reamer is located and formed for effectiveaction.

Hence, an object of the present invention is to provide a novelstreamlined percussion drilling bit and reamer unit which satisfies theforegoing needs.

SUMMARY OF THE INVENTION Broadly, in one preferred embodiment, thepresent novel churn percussion drilling bit and reamer unit comprises astreamlined shaft or body having a reduced lower end. Mounted in andextending downwardly from the lower end is a row of elongated chisel bitelements or fingers. The center one may be of bullet-nose shape and theothers of half bullet-nose form, each group flanking the center elementfacing in a predetermined direction for spinning cutting or scraping, orall may be bullet-shaped. Affixed to the shaft above the said cuttingelements and separated therefrom, a novel arrangement, are spacedreamers formed for effective reaming and minimum withdrawal sticking.

In another preferred embodiment, the bit is expandable. Two spacedblock-like teeth extend down from cavities in the lower end of thestreamlined shaft, each of which includes an elongated cutter insert ofcarbide or other suitable material, although for some uses, the teethmay be of tool steel. A downwardly extending partition wall separatesthe teeth, a heavy bolt extending through the teeth and wall securingthe teeth in place. Shims are provided for disposition between saidteeth and wall to maintain the teeth in the desired expended positionswhich are readily insertible on removal of the bolt.

Other objects are to provide novel cable percussion drilling bit andreamer units which find particular adaptation to a multiple blowdrilling structure, but are useful otherwise as well, which are highlyefiicient and effective, which reduce to a minimum recrushing of cutrock, which maintain a substantially straight hole, which reduceresharpening of the cutting elements to a minimum, which are expandableto maintain cutting size by use of simple tools, which substantiallyincrease inches per hour drilled, which are very durable, whicheffectively ream and reduce sticking in upward movement to a minimum, inwhich a tooth or teeth may be readily replaced at low cost, and whichotherwise fulfill the objects and advantages sought therefor.

The foregoing and other objects and advantages are apparent from thefollowing description, taken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view ofone preferred drill bit and reamer unit incorporating the teachings ofthe present invention;

FIG. 2 is an enlarged fragmentary view of the lower end thereof, aportion being in cross section for illustration of details;

FIG. 3 is a view similar to FIG. 2 rotated through ninety degrees, aportion being in cross section for illustration of details;

FIG. 4 is a further enlarged bottom plan view of FIG. 2;

FIG. 5 is a side elevational view of another preferred drill bit andreamer incorporating the teachings of the present invention;

FIG. 6 is an enlarged fragmentary view of the lower end of the bit ofFIG. 5;

FIG. 7 is a view similar to FIG. 6 rotated through ninety degrees;

FIG. 8 is a bottom plan view of FIG. 6;

FIG. 9 is an enlarged horizontal cross-sectional view on substantiallythe line 9-9 of FIG. 5;

FIG. 10 is a horizontal cross-sectional view on substantially the line1010 of FIG. 6;

FIG. 11 is a vertical cross-sectional view on substantially the line1111 of FIG. 7; and

P56. 12 is a view similar to FIG. 10 illustrating three teet DESCRIPTIONOF PREFERRED EMBODIMENTS Referring to the drawings more particularly byreference numerals and with specific reference to FIGS. 1-4, indicatesgenerally a cable percussion drilling bit and reamer unit constructed toinclude the principles of the present invention. The unit 10 includes ashaft 12 having a threaded reduced upper portion 14 and a reduced lowerportion 16 of the form clearly shown in FIGS. 2-4, terminating in aflat, narrow bottom surface 18 which reduces rock recrushing effects. Anelongated bullet-nose carbide steel chisel element 20 is mounted in andcentrally of the bottom surface 18, being secured in position by anydesirable means, as by press fit, silver solder, screw threads, or thelike. To each side of the element 20 are elongated half or fullbullet-nose carbide steel chisel elements 22, two being illustrated ineach group. Each element 22 is mounted so the cutting edge provided bycutting away one-half of the free nose faces in the normal direction ofspin of the unit 10 as it drops. The chisel elements 20, 22 may extendwell below the bottom surface 18, which reduces recrushing of cut orshattered rock or they may just protrude. No sticking occurs when theunit 10 is used with a multiblow drill structure. The elements 20 and 22may take other specific forms, all having a high unit load in drilling.

For churn drilling, the present structure provides a new method of rockstressing. The points of contact of the elements 20, 22 cause radialstress lines to overlap, which does not occur with standard bits. Hence,there is greater drilling effect, more rock being drilled.

Above the chisel elements 20, 22 and integral with the shaft 12 arereamers 24 spaced diametrically, each of which includes a carbide steelscraper 26 having a lower cutting edge 28 about ,4, outwardly of anupper reaming edge 30 for maximum reaming with minimum sticking on thewithdrawal of the unit 10, as clearly shown in the drawings.

The elements 20, 22 and the reamer scrapers 26 may be of other suitablematerial, as tungsten carbide.

In FIGS. 5-11 is shown another preferred embodiment of the presentinvention, the unit being indicated generally by the reference numeral30. The unit 30 includes a shaft 32 having a threaded reduced upper end34 and a lower end 36 having two cavities or chambers 38 open at theends and bottom and separated by a depending partition or wall 40.

A tooth 42 of block forming including a round hole 44 with an enlargedleading portion 46 and having an sert 48 of carbide or other suitablematerial and of the configuration shown in the drawings is mounted inone cavity 38. A second tooth 50 is like tooth 42, except for a threadedhole 52 instead of the hole 44. The teeth 42 and '50 may be solid goodsteel. A heavy bolt 54 with a head 56 extends through the hole 44, ahole 58 in the partition 40, and threadedly engages the hole 52 tomaintain the teeth 42 and 50 in operative positions. The hole 58 is alittle larger than the diameter of the bolt 54 to prevent undue impacton or contact with the bolt 54 in drilling to prevent stressing orbinding of the b lt 54. It is understood that variations may be made inthe securing means, as a nut and bolt for the bolt 54, which would notrequire threads in the hole 52, but would need a space for a nut.Further, a single bolt 54 may be used to secure each of teeth 42 and 50,such bolts being anchored in the partition 40.

A shim '60 of metal or other suitable material is shown between each ofthe teeth 42 and 50 and the partition to maintain the proper drillingpositions of the teeth 42 and 50. It will be understood that more shimswill be added as the teeth wear in drilling. This can be readilyaccomplished in the field by removal and replacement of the bolt 54 withsimple tools. The teeth 42 and are of good tool steel or other suitablematerial.

A button 62 of carbide and the like may be secured in the bottom of thepartition 40 to break up center crowns and the like.

Reamers similar to the reamers 24 may be used with the unit 30, orinserted on the lower end 36, as the reamers 64 above teeth 42 and 50,or as integral part of the teeth 42 and 50 above the carbide inserts 48indicated 66 in the dotted lines in FIG. 7 only. However, the unit 30will drill effectively without reamers.

In FIG. 12 is illustrated a modication of the expandable unit 30designated 70 in which a center post 72 replaces the partitions 40.Three teeth 74 are shown, each secured in position by a bolt 76, theholes through the teeth 74 being a little large to prevent shock and toallow tooth movement without binding. More teeth could be used. In onecomparative test, a standard drop drilling stem with standard fieldforged bit drilled a segment of six inch holes at a rate of 8"9" perhour in green granite in Connecticut. A chatter hammer with a standardfield forged bit under the same conditions drill 18-24 per hour. Achatter hammer with the bit unit 30 above described under the sameconditions drilled 36"-48 per hour. Other comparative tests havedemonstrated the same outstanding improvement.

Shimming of the teeth 42 and 50 increases the cutting life of the unit30 several fold. Tests in Connecticut green granite demonstratedapproximately ,4, of overall gage lost per 30 feet of drilling with theunit 30. By use of shims '60, nearly 1000 feet may be drilled with oneset of teeth 42, 50 as against 300'-350' obtained from comparable fixedbits. It is to be understood that the wear referred to decreases thesize of the bit so that it becomes too small for the hole size beingdrilled.

It is apparent that there has been provided units which fulfill theobjects and advantages sought therefor.

It is to be understood that the foregoing description and theaccompanying drawings have been given by way of illustration andexample. It is also to be understood that changes in form of theelements, rearrangement of parts, and substitution of equivalentelements, which will be obvious to those skilled in the art, arecontemplated as within the scope of the present invention which islimited only by the claims which follow.

What is claimed is:

1. In combination, a drilling unit for churn drills and the like,comprising a body including a lower end, drill teeth mounted in thelower end for drilling, and means for moving the drill teeth generallyradially of the body as needed for the required drilling width of thedrilling unit.

2. The combination of claim 1 including a crushing member secured to thebottom of the lower end.

3. The combination of claim 1 and including a reamer secured to eachtooth.

4. The combination of claim 1 and including means for receiving andholding shim means in effective relation to said teeth to providerequired drilling width.

5. The combination of claim 1 in which two cavities are formed in thelower end of the body, a partition wall separating the cavities, a toothin each cavity, and bolt means securing the teeth against the partitionwall.

6. The combination of claim 5 in which at least one shim is disposedbetween each tooth and the partition wall.

7. The combination of claim 6 in which the bolt extends through a holein the partition wall, said hole being of sufiicient larger diameterthan the bolt to substantially eliminate destructive pounding on thebolt in drop drilling.

8. The combination of claim 1 in which multiple cavities are formed inthe lower end of the body about a central post, a tooth in each cavity,and means securing the teeth in the cavities.

9. The combination of claim 8 in which at least one shim is disposedbetween at least one tooth and the post.

References Cited UNITED STATES PATENTS 178,220 5/ 1876 Yarborough -26 3(Other references on following page) UNITED STATES PATENTS Duncan175-407 X Caldwell 175-384 X Rogers 175-384 X Hill 175-384 Lee 175-263X. Backer 175-407 Sanderson 175-414 X Bannister 175-383 Campbell 175-403Stephens 175-382 X Atkinson 175-414 X Baumgartner 175-407 Phipps 175-410X Christensen 175-410 X Fowler 175-410 ERNEST R. PURSER, PrimaryExaminer R. E. FAVREAU, Assistant Examiner US. Cl. X.R.

